[Ace-users] [ace-users] [ace-bugs] [asnmp]: [agent PDU receiving bug]

[Douglas C. Schmidt]

Hi Johnny,

>Thanks for using the PRF form. Wouldn't your change result in a possible
>memory leak?

Can you please explain what would cause a memory leak?

Thanks,

Doug

>Regards,
>
>
>Johnny Willemsen
>Remedy IT
>Postbus 101
>2650 AC  Berkel en Rodenrijs
>The Netherlands
>www.theaceorb.nl / www.remedy.nl  
>
>*** Integrated compile and test statistics see
>http://scoreboard.theaceorb.nl ***
>*** Commercial service and support for ACE/TAO/CIAO             ***
>*** See http://www.theaceorb.nl/en/support.html                 ***
>
>
>
>"Artem Nikitin" <nikitin at komset.ru> wrote in message
>news:<mailman.3511.1201843967.5286.ace-bugs at mail.cse.wustl.edu>...
>> ACE VERSION: 5.5, released Sun Mar 05 11:10:32 2006.
>> 
>> HOST MACHINE and OPERATING SYSTEM:
>>      MS Windows 2000, WINSOCK 2.0 (Product version 5.00.2195.6601 and
>>      5.2.3790.3959)
>>      
>> TARGET MACHINE and OPERATING SYSTEM, if different from HOST: -
>> COMPILER NAME AND VERSION (AND PATCHLEVEL):
>>    C++ compiler MS Visual Studio.NET 2003 (with SP1)
>> 
>> AREA/CLASS/EXAMPLE AFFECTED: asnmp library, sagent class
>> 
>> DOES THE PROBLEM AFFECT:EXECUTION
>> 
>> SYNOPSIS: PDU receiving bug
>> 
>> DESCRIPTION:
>> I work with asnmp
>> library and "sagent" class for creating my simple SNMP agent.
>> 
>> I got non-null('\0') terminated string when receive PDU from manager in
>the
>> "get_community" method of "wpdu" class. My call stack was damaging.
>> 
>> REPEAT BY:
>> ....
>>  char rcv_com_str[MAX_COMM_STR_LEN];
>>  transaction tr(_snmp_session_);
>>  tr.handle_input(fd);
>>  if (tr.result(pdu_, rcv_com_str) < 0)  // damaging call
>>     return 0;
>> ....
>> 
>> 
>> // return pdu to caller
>> int transaction::result(Pdu& pdu, char *comm_str, ACE_INET_Addr *from)
>> {
>>   // TODO: check to see the sender matches the receiver address..
>> 
>>   // remove any vbs existing in this pdu
>>   pdu.delete_all_vbs();
>> 
>>  // any data to return?
>>  if (receive_iovec_.iov_len == 0)
>>    return -1;
>> 
>>  wpdu tmp(receive_iovec_);
>> 
>>  snmp_version ver;
>> 
>>  // return comm str and from address of incomming pdu if requested
>>  int rc = tmp.get_pdu(pdu, ver);
>>  if (comm_str) 
>>    strcpy(comm_str, (char *)tmp.get_community());
>>  if (from)
>>   *from = receive_addr_;
>>  return rc;
>> }
>> 
>> SAMPLE FIX/WORKAROUND:
>> 
>> wpdu.cpp file:
>> 
>> void wpdu::get_community(char* target) const
>> {
>>   strncpy(target, community_name, comm_len);
>> }
>> 
>


-- 
Dr. Douglas C. Schmidt                       Professor and Associate Chair
Electrical Engineering and Computer Science  TEL: (615) 343-8197
Vanderbilt University                        WEB: www.dre.vanderbilt.edu/~schmidt
Nashville, TN 37203                          NET: d.schmidt at vanderbilt.edu